Ericsson Gmbh

Torbjorn Wilson Solve

Larry William Massingill

Edward V Jolley

Mark Ranta

Amer A Hassan

Paul Wilkinson Dent

Paul W Dent

Javor Kolev

Thomas M Croft

Gregory A O'Neill, Jr

Eric Yi-Pin Wang

Jim A Rasmusson

Richard Edward Weiss

Robert Allen Zak

Stan L Reinhold

Daniel Wickstrom

Methods and systems are provided for determining a position of a mobile terminal that includes a satellite radiotelephone and a global positioning system (GPS) receiver based on knowledge of the position of the communication satellite spot-beam in which the mobile terminal is located. Using knowledge of the location of the communication satellite spot-beam, the present invention can resolve the one-millisecond ambiguity, that typically arises from the code repeat length where relative code phase may be determined but absolute code phase (i.e. one millisecond increments) could be off by one or more code periods. The spot-beam identifier is obtained from the satellite communication system and used to determine the geographic location of the spot-beam. Trial positions, i.e., candidate mobile terminal positions, are then selected to cover the spot-beam area, with spacing between trial positions provided to account for the one-millisecond ambiguity. Pseudo-range measurements are generated for each trial position and used to generate position fixes. The best position fix, for example a fix selection based on a self-consistency check, is then selected as the mobile terminal's position. In an additional aspect of the present invention, the number of trial positions is reduced by selecting an arc of positions within the spot-beam as trial positions based on timing delay information from the satellite communication system.

Systems and methods for resolving GPS pseudo-range ambiguity

Methods and systems are provided for synchronization of a mobile terminal to a communication system which provide faster access to the communication system and reduced risk of non-productive battery power consumption. In particular, the methods and systems of the present invention test one candidate carrier from a list of candidate carriers and perform a power profile to obtain an indication of signal strength of the carrier. This signal measurement is then compared to a threshold criteria. If the criteria is satisfied, the mobile terminal attempts synchronization with that carrier and, if successful, establishes a connection with the communication system. If the criteria is not satisfied, another candidate carrier is selected and tested similarly. Furthermore, the methods and systems of the present invention provide for tiered searching for a valid carrier with each level providing an increased likelihood of finding a carrier while, potentially, requiring a greater amount of time to obtain synchronization. The methods and systems of the present invention also provide a hierarchical approach to searching when no carrier has been identified which reduces the rate of battery power consumption while the mobile terminal is attempting to synchronize with a communication system.

Systems and methods for fast terminal synchronization in a wireless communication system

A user terminal provides communications to and from a radiotelephone communications system. This radiotelephone communications system supports communications with the user terminal at a first power level and paging to the user terminal at a second power level greater than the first power level. In addition, a page includes an indication when voice mail has been received at the radiotelephone communications system. In particular, the user terminal includes a transceiver, a processor, and a user interface. The transceiver receives communications from the radiotelephone communications system at the first power level, transmits communications to the radiotelephone communications system, and receives pages from the radiotelephone communications system at the second power level. The processor processes the pages to determine when voice mail for the radiotelephone has been received at the radiotelephone communications system, and the user interface provides an indication to a user when voice mail for the user terminal has been received at the radiotelephone communications system. Related methods and communications systems are also discussed.

Communications systems for transmitting high power voice mail notifications and related methods and user terminals

A wireless telephone having a wireless communication transceiver, a global positioning system (GPS) receiver, and a controller connected to both the wireless communication transceiver and the GPS receiver, wherein the controller intelligently adapts its GPS data maintenance schedule according to a unique set of indicators derived from the wireless telephone's operating conditions.

System and method for conserving battery energy in a wireless telephone

A method and apparatus for reducing power consumption in a mobile terminal having a receiver for receiving a time multiplexed message distributed over a plurality of time slots by receiving a first subset of the plurality of time slots so as to receive a first portion of the time multiplexed message corresponding to the first subset of the plurality of time slots. The mobile terminal then determines from the first portion of the time multiplexed message if additional time slots of the time multiplexed message need to be received by the mobile terminal. The mobile terminal receives a second subset of the plurality of time slots so as to receive a second portion of the time multiplexed message if the mobile terminal determines from the first portion that additional portions of the time multiplexed message are to be received by the mobile terminal. This first portion of the message is preferably independently decodeable from the remainder of the message.

Methods and systems for reduced power operation of cellular mobile

A method for increasing the control channel capacity of a control station in a communications system. According to the method, in an idle mode of operation, a mobile station receives and processes data during more than one time slot per frame. As a result, additional channel structures are made possible such that additional data can be broadcast to a mobile station without restructuring a conventional slot format.

Method for increasing control channel capacity in a communication system

A method for distinguishing between in-band signaling and user data transmissions of a communication system. The method includes the assignment of separate training bit sequences, one for in-band signaling transmissions and another for user data transmissions. During transmission, the training bit sequence associated with the type of transmission being sent is used as the training bit sequence. The method further includes the correlation of the received training bit sequence with both the training bit sequence assigned to in-band signaling and the training bit sequence assigned to user data. The training bit sequence having the highest correlation energy indicates the type of data contained in the communication transmission.

Method and apparatus for distinguishing in-band signaling from user data

A power saving method for maintaining synchronization in a power-limited communication system, such as a satellite-based TDMA mobile radiocommunication system. According to exemplary embodiments, the satellite transmits abbreviated bursts containing only synchronization information during intervals when no other control information is required by the receiving mobile unit, reducing power consumption during these intervals.

Power-saving method for providing synchronization in a communications

A synchronization method and apparatus for synchronizing a receiver, such as a radiotelephone operable in a cellular communication system with a transmitter. Synchronization signals are transmitted as parts of a control signal to the receiver. Such synchronization signals are of high margins and also permit synchronization of the radiotelephone responsive to a reduced number of calculations. The time for such synchronization is reduced by use of nonlinear transformation metrics, such as logarithmic metrics, which reduce the impact of a noise or error component within the control signal.

Synchronization method, and associated circuitry, for improved

A method and apparatus for reducing the echo in a hands-free digital cellular communications system is presented. Acting upon speech signals being present in the downlink, uplink speech frames generated by the hands-free communication device are attenuated to prevent the downlink speech signals from being transmitted at full volume back on the uplink as an echo. Added to the attenutated uplink speech frame is a noise frame generated by the hands-free communication device, which provides a consistent level of background noise to the person at the other end of the call. The noise codeword is further randomly ordered to prevent any modulative effects from the process.

Method and apparatus for echo reduction in a hands-free cellular radio

An echo canceling loudspeaker telephone includes a loudspeaker which produces a sound pressure wave in response to an input signal which is applied to an audio input thereof. This sound pressure wave includes a desired linear component which is a linear function of the input signal, and an undesired non-linear component which is a non-linear function of the input signal, and the sound pressure wave is transmitted along an acoustic path. A microphone is positioned in the acoustic path and converts the sound pressure wave into an output signal. An echo filter is responsive to the input signal and generates an estimated echo signal. This echo filter includes a loudspeaker model which generates an estimate of the sound pressure wave including an estimate of the linear component and an estimate of the non-linear component. This echo filter also includes an acoustic path model which generates an estimate of the acoustic path from the loudspeaker to the microphone. In addition, a subtractor subtracts the estimated echo signal from the output signal thereby reducing an echo portion of said sound signal.

Apparatus and method for canceling acoustic echoes including non-linear

In a digital FM receiver having a demodulator that receives a radio signal and generates therefrom a phase sample whose behavior determines an output of the demodulator, an apparatus for removing a low-frequency interference signal from the phase sample converts the phase sample into a frequency sample which is then high-pass filtered to produce a filtered frequency sample. The filtered frequency sample is then converted into a filtered phase sample, which may be further demodulated in accordance with known techniques. Converting the phase sample into a frequency sample may be performed by a first order difference circuit. Converting the filtered frequency sample into the filtered phase sample may be performed by an integrator. Because the demodulator may produce degraded performance when the inventive apparatus is applied to a radio signal that does not have low-frequency interference, in another aspect of the invention the demodulator is further provided with a circuit for detecting the presence of the low-frequency interference signal in the radio signal, and alternatively selecting, in response thereto, either the filtered or original phase sample to be supplied to further demodulation circuitry.

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Cary, NC, United States of America

Torbjorn Wilson Solve